The present invention relates to a vehicle-mounted airbag apparatus, such as a driver's seat airbag apparatus installed at a central portion of a steering wheel. More particularly, the present invention relates to an airbag apparatus comprising an air bag which deploys between the vehicle and a passenger by means of a gas generated by a gas generator.
For example, a bag body for an airbag apparatus is disclosed in Japanese Laid-Open Utility Model Publication No. 6-51022. The bag body, disposed at a central portion of a steering wheel, expands between the steering wheel and a passenger upon sudden deceleration of a vehicle, and therefore is capable of protecting the passenger. In this bag body, a portion corresponding to the space between the lower portion of the steering wheel and the chest of the passenger expands less than a portion corresponding to the space between the upper portion of the steering wheel and the head of the passenger.